The aim of the present article is to classify a collection of quantum states of the matter in a generic curved spacetime, satisfying NEC. For the sake of mathematical simplicity, we use a non-interacting real scalar field theory. In order to classify these quantum states, we use coherent state descriptions since we follow the canonical approach to QFTCS [1]}, [2]}, [3]}. We also briefly discuss the classification of quantum states based on ANEC.
